floss: metrics: emit bond state event to gd/metrics

Introduce new topshim APIs to emit bond state events from rust to gd/metrics.

BUG: 232098615
Tag: #floss
Test: emerge-${BOARD} floss
Test: ./build.py
BYPASS_LONG_LINES_REASON: Bluetooth likes 120 lines

Change-Id: Ic8fb319351ef18820293fa2eed45dbc333e2119d